Figure 5

Excitability changes after injury in EP components by hand stimulation. (A) Amplitude distribution of MF (latency <10 ms) and CF (latency > 10 ms) components. EPAs were normalized (nEPA) to a maximum recorded amplitude on any day throughout the pre-/post injury period in each rat, and then a z-score value was applied as a threshold (Zscore > 2.05, 15 MFs and 71 CFs). The data were gathered from 4 rats as indicated by different marker shapes. While CF-EPAs indicated the strongest responses in the pre-injury (control) recordings in all animals (blue markers, T = 14/19 trials; Zscore > 2.05), MF-EPAs showed supra-threshold responses only in the post-injury period (T = 15/89 Trials, Zscore > 2.05), except day-3. (B) Same data with a lower threshold (Zscore > 1.55) were averaged and shown as mean ± s.d for MF (red) and CF (blue), respectively. Statistical analysis indicated significant increases in MF-nEPAs, and significant decreases in CF-nEPAs in the post-injury period (ANOVA followed by Dunnett’s test; control vs. post-injury time points, n = 5 days, n = 32 MF-nEPAs, n = 105 CF-nEPAs; ***P < 0.001, **P < 0.01, *P < 0.05). Individual days were compared using pairwise t-test (CF ~1 h vs. day-1; ^!!!P = 0.0013, NS: Not significant).